Rheological characterisation of sol–gel phenomenon and stability of green gram and foxtail millet flour gels

Abstract

The sol–gel transition was investigated employing temperature sweep tests from 60 to 25 °C. Four model sol dispersions, prepared from the green gram and foxtail millet flour, and their isolated starches, were examined. The formed gels were determined by performing the low strain (5%) stress relaxation test. The gelling temperatures were 38–47 °C for all the flour/starch gels. The starting gelling temperatures were about 2 to 3 °C higher than their corresponding average gelling temperatures. At the sol and gel states, the ratio of storage and loss moduli was between 7 and 9, and between 11 and 19, respectively. The different stability indices related to rheological characteristics followed either a zero or first order kinetics. The application of principal component analysis indicated that sols/gels made from foxtail millet flour and both starches, the average and starting gel temperatures behaved in a similar manner.